Challenge.gov's similar web sites are shown below:

Detailed Analysis:

The site Challenge.gov's front page was last entered
by gilturl 16-11-2012. The source was comprised
of 127 characters, of which 244 are code, leaving an organic
character count of 200. The total specialized word count on the Challenge.gov
home page is 135. We calculated that number of unique words is 254. We extracted 420 top
keywords, leaving 56% above the threshold. Total Phrases
above the threshold was 990.